Territory Stories

Alice Springs recreational dam hydrology report project 6

Details:

Title

Alice Springs recreational dam hydrology report project 6

Creator

Jackson, D.; Paige, D.

Collection

E-Publications; E-Books; PublicationNT; Report no. 12/1979

Date

1979-10-01

Notes

Date:1979-10

Language

English

Publisher name

Northern Territory Government

Place of publication

Darwin

Series

Report no. 12/1979

File type

application/pdf

Use

Attribution International 4.0 (CC BY 4.0)

Copyright owner

Northern Territory Government

License

https://creativecommons.org/licenses/by/4.0/

Parent handle

https://hdl.handle.net/10070/228346

Citation address

https://hdl.handle.net/10070/674275

Page content

Technical Report WRD79012 Viewed at 00:02:46 on 18/02/2010 Page 30 of 153. I I I I I I I I I I I I I I I I I I I I 16 Table II ESTIMATED FLOOD FREQUENCY AT DAMSITE Return Period (years) 5 10 20 50 Peak Annual Discharge 3 (m Is) 350 490 650 850 100 1000 500 1400 3.3 Unitgraphs using th-e method of unitgraph derivation develop-ed by Ash (1973) two one hour unitgraphs were derived for the Todd River at G.S. 006046 and at G.B. 006009. They are shown in Figure 8. Many of the recorded hydro graphs were found to be unacceptable for use in the Ash Method because they were either multiple peaked or the peak discharge was too small to be regarded as a flood. The method only allows sharply peaked hydrographs to be considered. At G.S. 006046 the unitgraph was derived from floods on the following dates: 17/4/61, 15/5/63, 13/10/64, 21/1/66, 6/1/76, 2/3/68, 30/12/73, 14/3/77, and 25/11/77. At G.S. 006009 the floods occuring on the following dates were used: 23/2/56, 15/5/63, 25/11/73, 15/12/75, 15/3/77 and 21/11/77. The unitgraph for G.S. 006009 has a longer recession limb and a steeper rising limb. This is partly due to the input from the Charles River. Response time of the Charles River is quicker than the response time of the Todd River and this influences the time of the rising limb at G.S. 006009. An average unitgraph (Figure 8) has been developed for input of hydrographs to the reservoir for examination of flood routing effects of the dam. 3.4 Maximum Probable Flood Estimates of the maximum probable flood have been derived from three sources.